In recent years, in the field of medical diagnostic imaging systems such as X-ray computed tomography (CT) scanners, magnetic resonance imaging (MRI) machines and ultrasonic diagnostic scanners, devices capable of generating three-dimensional medical imaging volume data have been in practical use. In addition, technologies for rendering volume data from an arbitrary viewpoint have been in practical use, and it has recently been attempted to display volume data three-dimensionally on a three-dimensional image display device.
With a three-dimensional image display device, viewers can view three-dimensional images with naked eyes without using special glasses. Such a three-dimensional image display device displays a plurality of images (each of which will be hereinafter referred to as a parallax image) from different viewpoints and controls rays for these parallax images with a ray control element unit such as a parallax barrier or a lenticular lens. In this process, an image to be displayed needs to be one obtained by rearrangement so that intended images are observed in intended directions when viewed through the ray control element unit. A method for the arrangement will be referred to below as pixel mapping, and various pixel mapping methods have been known in related art. Rays controlled by the ray control element unit and by pixel mapping therefor are guided to the eyes of a viewer, who can then recognize a three-dimensional image if the viewer is at an appropriate viewpoint. A zone that enables a viewer to view a three-dimensional image in this manner is referred to as a viewing zone.
The number of viewpoints in generating parallax images is determined in advance, which is typically not sufficient for determining luminance information of all pixels of a display panel. Accordingly, for pixels to which parallax images associated with respective predetermined viewpoints are not assigned (for pixels for which luminance information is not determined from parallax images), the luminance information thereof needs to be determined by performing interpolation using parallax images for a nearest viewpoint.
Since parallax images for different viewpoints are blended as a result of the interpolation, a problem occurs such as generation of a multi-layered image that is observed as having two or more overlapping edge portions where one edge portion should originally be observed or blurring of the entire image.